Current typical gauging methods for a cam or bearing profile use a single gauging pass around a periphery of a surface of the cam or bearing surface. In order to characterize the level of ‘crown’ or ‘taper’ on a cam lobe, for example, often three passes have been used, one around a center of a lobe, followed by one pass near each edge of the lobe. Historically, in order to compute crown or taper, averages of radial deviations from the ideal size/profile about the circumference have been computed for each of these three passes, yielding a single deviation value for each of the three passes. Differences between these three values are typically used to compute a pair of single numbers. One of the numbers from the pair characterizes the crown and the other number characterizes the taper for the entire surface.
This averaging method, however, does not allow for the possibility of severe local surface irregularities that effectively cancel each other out in the traditional crown and taper computations. Furthermore, no meaningful insight is given into actual surface shape of the cam or bearing which might be used to refine the manufacturing process or correlate to bearing performance or durability data.